Project description:The ability of Entamoeba histolytica to phagocytose host cells correlates to observed virulence in vivo. To better understand the mechanism of phagocytosis we used paramagnetic beads coated with host ligand and sorted trophozoites based on phagocytic ability. Gene expression was then measured in both the sorted phagocytic and non-phagocytic populations using a custom Affymetrix chip for E. histolytica. Feed forward regulation of phagocytosis by Entamoeba histolytica. Infection and Immunity. PMID 23045476
Project description:A myb domain containing protein of the SHAQKY family, EhMyb-dr, was overexpressed in E. histolytica trophozoites, and effects on transcription were measured.
Project description:The ability of Entamoeba histolytica to phagocytose host cells correlates to observed virulence in vivo. To better understand the mechanism of phagocytosis we used paramagnetic beads coated with host ligand and sorted trophozoites based on phagocytic ability. Gene expression was then measured in both the sorted phagocytic and non-phagocytic populations using a custom Affymetrix chip for E. histolytica. Feed forward regulation of phagocytosis by Entamoeba histolytica. Infection and Immunity. PMID 23045476 M280 Streptavidin Dynabeads (Invitrogen) were labeled with 20ug/mL biotinylated Human C1q (Quidel). Entamoeba histolytica (strain HM1) were washed twice with PBS then resuspended with the labeled beads at a 10:1 ratio of beads to trophozoites. Samples were incubated at 37°C for 45 minutes, washed twice with agitation to remove adherent beads, then resuspended in MACS buffer. Samples were loaded into magnetic columns (Miltenyi Biotec) and trophozoites were seperated according to manufacturer's protocols. phagocytic vs. non-phagocytic Entamoeba histolytica populations
Project description:A myb domain containing protein of the SHAQKY family, EhMyb-dr, was overexpressed in E. histolytica trophozoites, and effects on transcription were measured. Two arrays of trophozoites expressing Myc tagged EhMyb-dr were compared to two arrays performed on wild type trophozoites. The effects of transfection and drug were controlled for by including data from trophozoites expressing irrelevant plasmids, and grown in the same level of G418. All parasites were of strain HM-1:IMSS
Project description:Entamoeba histolytica trophozoites epigenetically silenced for ameobapore A (G3 parasites) were additionally silenced for the Rhomboid gene Rom1 (EHI_197460) using the mechanism outlined in Mirelman et al. Parasite. 2008 Sep;15(3):266-74 (PMID 18814693). Rom1 silencing was confirmed by RT-PCR. Gene expression in these parasites was compared to that of the parent G3 strain.
Project description:Quinoxalines are heterocyclic compounds that contain a benzene ring and a pyrazine ring. The oxidation of both nitrogen of the pyrazine ring results in quinoxaline derivatives (QdNO), which exhibit a variety of biological properties, including antiparasitic activity. However, its activity against Entamoeba histolytica, the protozoan that causes human amebiasis, is poorly understood. Recently, our group reported that various QdNOs produce morphological changes in E. histolytica trophozoites, increase reactive oxygen species, and inhibit thioredoxin reductase activity. Notably, T-001 and T-017 derivatives were among the QdNOs with the best activity. In order to contribute to the characterization of the antiamebic effect of QdNOs, in this work we analyzed the proteomic profile of E. histolytica trophozoites treated with the QdNOs T-001 and T-017, and the results were correlated with functional assays. A total number of 163 deregulated proteins were found in trophozoites treated with T-001, and 131 in those treated with T-017. A set of 21 overexpressed and 24 under-expressed proteins was identified, which were mainly related to cytoskeleton and intracellular traffic, nucleic acid transcription, translation and binding, and redox homeostasis. Furthermore, T-001 and T-017 modified the virulence of trophozoites, since they altered their erythrophagocytosis, migration, adhesion and cytolytic capacity. Our results show that in addition to alter reactive oxygen species, and thioredoxin reductase activity, T-001 and T-017 affect essential functions related to the actin cytoskeleton, which eventually affects E. histolytica virulence and survival.
Project description:Invasion of the colon wall by Entamoeba histolytica during amoebic dysentery entails migration of trophozoites through tissue layers that are rich in extracellular matrix (ECM). Transcriptional silencing of the E. histolytica matrix surface metalloprotease EhMSP-1 produces hyper-adherent, less motile trophozoites that are deficient in forming invadosomes. Reversible protein phosphorylation is often implicated in regulation of cell motility and invadosome formation. To identify such intermediaries of the EhMSP-1 silenced phenotype, here we compared the phosphoproteome of EhMSP-1 silenced and vector control trophozoites using quantitative mass spectrometry based proteomics. Six proteins were found to be differentially phosphorylated in EhMSP-1 silenced and control cells, including EhCoactosin, a member of the ADF/Cofilin family of actin binding proteins, which was hyperphosphorylated at serine 147 (S147). Regulated over-expression of wild type, phosphomimetic (S147D), and non phosphorylatable (S147A) EhCoactosin variants was used to test if S147 phosphorylation functions in control of E. histolytica actin dynamics. Each of the over-expressed proteins co37 localized with F-actin during E. histolytica phagocytosis. Nonetheless, trophozoites overexpressing EhCoactosin S147D formed more and poorly coordinated small membrane protrusions compared to control or S147A expressing cells, while trophozoites overexpressing EhCoactosin S147A were significantly more motile within a model of mammalian ECM. Therefore, although EhCoactosin’s actin-binding ability appeared unaffected by S147 phosphorylation, EhCoactosin phosphorylation helps to regulate amoebic motility. These data help to understand the mechanisms underlying altered adherence and motility in EhMSP-1 silenced trophozoites, and lay the groundwork for identifying kinases and phosphatases critical for control of amoebic invasiveness.
Project description:Entamoeba histolytica is a protozoan parasite which causes colitis and liver abscesses. Using a genomic DNA microarray consisting of 1.6 - 2.0 kb genomic inserts we have generated a transcriptional profile of 1,971 unique parasite transcripts. The 12 arrays in this experiment set were used to estimate relative transcript abundance for Entamoeba histolytica (HM-1:IMSS) trophozoites in mid-logarithmic growth.